This invention relates to air distribution systems and deals more particularly with air conditioning distribution systems having self-powered controls.
In our co-pending U.S. Pat. application Ser. No. 306,559, filed Nov. 15, 1972, now U.S. Pat. No. 3,837,571 entitled "Self-Controlled Air Distribution System", there is disclosed an air distribution system having a fluidic control system powered by duct air pressure. The air distribution system disclosed therein utilizes a variable restrictor, associated with the thermostat, for establishing a pressure reference signal for comparison with actual duct pressure. As a result, the temperature sensitivity of the thermostat is a function of the maximum pressure setting.
It is desirable to have a distribution system in which the temperature sensitivity is not affected by variations in the maximum pressure setting and, correspondingly, the maximum output of the system. This goal cannot be achieved in the system disclosed in the referenced U.S. patent application because of the variable restrictor which inhibits air delivery throughout the entire temperature control range.
It is also known to utilize a secondary conditioning apparatus in an air distribution system to locally heat or cool the conditioned air from a remote source such as a central air conditioner. In the conditioning system having a fluidic control system regulating the discharged air, it is desirable that the secondary conditioning system also be fluidically controlled. It has been found that fluidic controls for a secondary system can be advantageously integrated with discharge controls and the two controls may share common sensors.
It is, accordingly, a general object of the present invention to disclose an air distribution system having a temperature sensitivity which remains uniform in spite of variations in the desired maximum output and which distribution system employs fluidic controls for regulating the discharge and secondary conditioning systems.